Electric contact and connector terminal pair
An electric contact that includes a first contact and a second contact that are capable of forming electrical contact with each other, wherein: the first contact has a silver-tin alloy layer exposed at an outermost surface that comes into contact with the second contact, the second contact has a silver layer exposed at an outermost surface that comes into contact with the first contact, and a surface roughness of the silver-tin alloy layer of the first contact is larger than a surface roughness of the silver layer of the second contact.
1. An electric contact comprising:
a first contact and a second contact that are capable of forming electrical contact with each other, wherein:
the first contact has a silver-tin alloy layer exposed at an outermost surface that comes into contact with the second contact,
the second contact has a silver layer exposed at an outermost surface that comes into contact with the first contact, and
a surface roughness of the silver-tin alloy layer of the first contact is larger than a surface roughness of the silver layer of the second contact.
2. The electric contact according to claim 1 ,
wherein the silver-tin alloy layer of the first contact has a surface roughness Ra of 0.5 μm or more and 2.0 μm or less.
3. The electric contact according to claim 1 ,
wherein the first contact has a silver layer directly below the silver-tin alloy layer.
4. The electric contact according to claim 1 ,
wherein the silver-tin alloy layer of the first contact has a hardness of 150 Hv or more.
5. The electric contact according to claim 1 ,
wherein the silver layer of the second contact has a hardness of 50 Hv or more and 80 Hv or less.
6. The electric contact according to claim 1 ,
wherein at least one of the first contact and the second contact has a primer metal layer made of nickel or a nickel alloy between a base material and a layer that is exposed at the outermost surface.
7. The electric contact according to claim 1 ,
wherein the base material that forms the first contact and the second contact is made of any of copper, a copper alloy, aluminum, and an aluminum alloy.
8. The electric contact according to claim 1 ,
wherein the first contact is a contact having a bulge shape, and
wherein the second contact is a contact that has a plate shape and comes into electrical contact with an apex portion of the first contact.
9. The electric contact according to claim 1 ,
wherein a dynamic frictional coefficient between the first contact and the second contact is 0.4 or more.
10. The electric contact according to claim 1 ,
wherein a dynamic frictional coefficient between the first contact and the second contact is 0.1 or more.
11. The electric contact according to claim 1 ,
wherein a main phase of the silver-tin alloy layer of the first contact is a phase having a Ag 3 Sn composition.
12. A connector terminal pair comprising:
a pair of connector terminals that come into electrical contact with each other at a contact portion,
wherein the contact portion has the electric contact according to claim 1 .